LIU Sheng 1, WANG Yingying 2, MAN Yanjin 1, ZHU Baoxin 2, LI Ling 2, WANG Weiwei 2, WANG Xiaodong 2, WANG Hongsheng 2, SONG Tao 2, YANG Zhihua 3, LIU Wenjin 3
(1. Beijing Power Machinery Research Institute, Beijing 100074, China; 2. Shandong Industrial Ceramic Research and Design Institute Co., Ltd, Zibo 255000, Shandong, China; 3. Harbin Institute of Technology, Harbin 150001, Heilongjiang, China)
Abstract: The effects of powder type, particle size, impurity content and phase composition of commercial silicon nitride powder on material properties were studied. Density, bending strength, thermal conductivity, friction and wear properties and microstructure of silicon nitride ceramics from different powders were examined. The silicon nitride powder treated with methanol modified liquid for 20 min led to silicon nitride ceramics with optimized comprehensive properties, including density of 3.16 g·cm−3, bending strength of (727±20) MPa, thermal conductivity of 71.6 W·m−1·K−1, friction coefficient between Si3N4 ceramics and C/SiC ceramics of < 0.7 at 1200 ℃. The ceramics exhibited strong high temperature resistance to friction and wear.
Key words: silicon nitride; powder modification; microstructure; mechanical property; frictional property